High frequency wave signaling



Aug. 7, 1934. F. RIEBER HIGH FREQUENCY WAVE SIGNALING SYSTEM Filed Oct.18, 192'? INVENTOR Fr nk P/ber 2424 HIS ATTORNEY Patented Aug. 7, 1934UNITED STATES PATENT "OFFICE HIGH FREQUENCY WAVE SIGNALING SYSTEM Thisinvention relates to asignaling system, and especially to one in whichvery high frequency waves propagated through an elastic medium areutilized.

Extremely high frequency mechanical waves have heretofore been capableof propagation in an elastic medium as by the aid of quartz crystalssubjected to varying electric stresses. It has been found in such priorsystems that when it is attempted to propagate the waves in air or othergaseous mediums, the amount of energy imparted thereto is very smallindeed. This is due to the extremely small amplitude of vibration of thecrystal, which may be effective enough in solid or liquid media totransmit a large amount of energy, but which are incapable of verymaterially affecting a more diffused medium such as a gas.

It is one of the objects of my invention to make it possible topropagate such waves in air or other gaseous media of suflicientintensity to be useful concentric with electrode 11, in order to permitfor signaling.

I find that an electric spark oscillator is very well adapted to producethese mechanical waves; and it is accordingly another object of myinvention to make it possible to utilize such an electric sparkoscillator in an efilcient and convenient manner for that purpose.

High frequency elastic waves have the property of being projectible indefinite directions; and this property is found to be more pronounced asthe frequency increases. Therefore it is entirely feasible to providedirectional signaling as by proper reflectors, and also to determine thesource of such waves so directed, by a directional pick-up scheme. It isthus another object of my' invention to make it possible to secure suchdirectional effects in a simple and convenient manner.

It has been found that a flame under proper conditions is very sensitiveto such waves of high frequency; and I contemplate the use of such aflame for receiving the wave impulses.

Thus when such waves are received by a flame that is at its maximumstable height, the height of the flame is materially reduced, and itbecomes rough and produces a roaring sound. It is another object of myinvention to provide a flame receiver of this kind that is simple andconvenient for my purposes.

My invention possesses many other advantages, dhas other objects whichmay be made more easily apparent from a consideration of one embodimentof my invention. For this purpose I have shown a form in the drawingaccompanying and forming part of the present specification. I

shall now proceed to describe this form in detail, which illustrates thegeneral principles of my invention; but it is to be understood that thisdetailed description is not to be taken in a limiting sense since thescope of my invention is best defined by the appended claims.

Referring to the drawing:

Figure 1 is a schematic diagram of a complete system embodying myinvention; and

Figure 2 is a diagrammatic view of the receiving device that can be usedwith my invention.

In Figure 1 I show in general a wave transmitting system in which anoscillatory spark discharge is obtained between a pair of electrodes 11and 12, arranged substantially at the focal point of a reflector 13,shown as of parabolic form to produce a beam of waves. These electrodescan be supported in any appropriate manner; as for example, by the aidof insulation sapports14.

The electrode 11 is shown as adjustable in its support, and electrode 12is preferably hollow and compressed air or other gases to be passedbetween the electrodes. It has been found that when such a stream of airis passed between the electrodes, the energy transmitted in the form ofhigh frequency waves is increased. For supplying the compressed air, Ishow a container 15 from which leads a conduit 16 fastened to theelectrode 12. A valve 17 controls the passage of air to electrode 12.

The spark is energized or excited by the aid of an oscillatory circuitincluding inductance 18 and condenser 19, the spark electrodes beingconnected across both these elements. A coil 20 inductively coupled toinductance 18 serves to excite the oscillatory circuit. This coil issupplied with commercial alternating current through leads 21 andcontrolling impedance 22. When the system is in operation, the condenser19 periodically discharges and causes an oscillatory discharge betweenelectrodes 11 and 12. All this is well understood in connection with the.propagaof audibility; accordingly the ear alone can be used for pickingup these first impulses. However, the later impulses are inaudible, andmust be received by a special apparatus. In the present instance, suchan apparatus is shown as by a sensitive flame 23. This flame is formedat the restricted opening of a burner '24 (Fig. 2) fed with fuel throughconduit 25 from a fuel reservoir 26 holding fuel in compressed form. Theburner 24 can be supported in any appropriate manner, as by bracket 27.The passage of fuel can be controlled by valve 28. V

The flame 23 is protected from extraneous disturbances by a tube 29,transparent so as to permit the flame to be seen. Holes 30 can belocated near the bottom of this tube to-permit air to pass to the burner24. These holes are preferably shielded against a too violent passage ofair there-- through, so as to maintain flame 23 in proper operativecondition and without deleterious effect from local air disturbances.For ensuring against other mechanical disturbances, the whole flameproducing structure can be mounted on a resilient support 31, such asfelt or sponge rubber held in a container 32. I

In order that the flame 23 be influenced by the high frequencyvibrations, a thin diaphragm 33 is provided in an aperture in tube 29and adja cent the restricted opening 'of burner 24. This diaphragm mustbe made from very thin material. The thinnest possible layer of mica iswell adapted for this purpose, as it permits the ready passage of thehigh frequencyelastic waves. Alternatively, very thin aluminum foil orother light thin substances may be employed.

At the right hand portion of Figure l, I show a receiving system wherebythe waves can be focussed onto diaphragm 33, and preferably in such away that the direction of the source can be determined.

For this purpose, there is a reflector 34 (preferably parabolic) thatserves to converge the rays 35' from the source, which reflector ismounted to rotate on a vertical axis. Thus the reflector must be alinedwith the beam of waves 35' in order to produce any effect upon the flame23. Its alined position can be shown by a stationary scale 35 and apointer 36 that forms a part of the movable reflector structure. Thereflector structure includes a tube 37 rotatable on a stationarystandard 38. At the lower part of the tube 3'? the arm 39 is provided,forming the pointer 36 at its extremity, and also providing a verticalsupport 40 for reflector 34.

The manner in which the high frequency waves can be conducted todiaphragm 33 will now be described. The converging. rays reflected fromreflector 34 are caused to fall upon another reflector 41, thisreflector being arranged to be moved in unison with the main reflector34. This can be accomplished readily by mounting reflector 41 on asupport 42 that is carried at the upper end of tube 37.

The reflector 41 is so tilted that the rays reflected therefrom aredirected downwardly into standard 38, which is madehollow for thispurpose. These rays finally impinge, after perhaps several reflectionsfrom the inner wall of standard 38, upon a reflector 43 located near thebottom of the standard and positioned to direct the reflected wavesthrough a window 44 in the standard and toward diaphragm 33. The courseof the waves can be conflned by the aid of a tapered tube 45.

In order to receive signals and to determine their direction, theparabolic reflector 34 is rotated until the flame 23 is affected. Theposition of the reflector with respect to a flxed reference can then bedetermined by the aid of of pointer 36, and this corresponds also to thedirection of the transmitted waves. It is evident that if reflector 34be turned away from the source, there will be a diminished responsesince less energy is. directed into tube 38.

I claim:

1. A directional receiver for mechanical high frequency elastic waves,including a rotatable reflector, means providing a stationary sensitiveflame, and means whereby the waves reflected by said reflector aredirected to said flame.

2. The combination as set forth in claim 1, in which the reflector is soformed that it concentrates the received waves and passes it onto thesensitive region of the flame only when the reflector is alined with thetransmitted waves.

3. The combination as set forth in claim 1, in which the reflector is soformed that it concentrates the received waves and passes it onto thesensitive region of the flame only when the reflector is alined with thetransmitted waves, comprising another reflector movable in unison withthe first reflector, means forming a passageway into which said otherreflector directs the waves, and a tube interposed between the sensitiveregion of the flame and the passageway.

4. In combination, a hollow standard, means for forming a sensitiveflame arranged adjacent the standard, a tube rotatable on said standard,a parabolic reflector supported by the tube and having a horizontalaxis, another reflector also supported by the tube and arranged todeflect the waves from the parabolic reflector into the hollow standard,and means for affecting the flame by the waves received in saidstandard.

5. In combination, a hollow standard, means for forming a sensitiveflamearranged adjacent the standard, a tube rotatable on said standard, aparabolic reflector supported by the tube and having a horizontal axis,another reflector also supported by the tube and arranged to deflect thewaves from the parabolic reflector into the hollow standard, and'meansfor affecting the flame by the waves received in said standard,comprising a third reflector in the standard for reflecting the wavesthrough a window in the standard.

FRANK RIEBER.

